In M2M communication, the routing protocol design to support efficient wireless communication in a multi-hop fashion is extremely important, especially for energy constrained devices.
In order to assist dynamic routing in low power and lossy networks, the IETF Routing over Low-power and Lossy Networks (RoLL) develops a routing protocol, called RPL (Resource Location Protocol).
RPL is a distance vector routing protocol, in which nodes of the network build a Destination Oriented Acyclic Graph (DODAG) by exchanging distance vectors and root to a “controller”. Through broadcasting routing constraints, the root node (i.e., central control point) filters out the nodes that do not meet the constraints and select the optimum path according to the metrics. In the stable state, each node has identified a stable set of parent nodes and forwarded packets along the path towards the “root” of the DODAG. An example of DODAG is illustrated in FIG. 1.
However, RPL cannot well support multimedia services in wireless networks. For example, transmitting images in a multi-hop fashion in a harsh outdoor environment to monitor emergency accidents may expect high packet loss. Moreover, because of the hierarchical transmission structure, the nodes close to the root (for example nodes a and b in FIG. 1) may experience more traffic and energy consumption, thus being vulnerable to the energy depletion.
As a consequence, there is a need for a new technique for configuring a network improving at least one of communication reliability and energy efficiency, for example in a low power and lossy networks.